The present application relates to a rolling diaphragm construction, and to a piston-cylinder assembly including such a rolling diaphragm. The invention is particularly useful for suction or compression pumps using rolling diaphragms, for example as described in my copending patent application Ser. No. 06/833,195, and is therefore described below with respect to such pumps.
Rolling diaphragms are commonly used for coupling a piston to a cylinder, but the known constructions of rolling diaphragms usually have some or all of the following drawbacks: they require some type of independent fastener element, such as bolts or the like, to fasten them both to the piston and to the cylinder in an airtight manner; they require some bearing to center the piston, if the piston is floatingly mounted and not guided by bearings; they require a bolt pattern or key to align the piston to the cylinder in an angular relationship; they cannot be slid into place as an assembly unless they are fastened together; they tend to spring air leaks when the pressure exceeds a predetermined level; in their manufacture, they are not always easy to remove from the mould if their shape is complex; and they operate with the pressure on one side only.
An object of the present invention is to provide a rolling diaphragm having advantages in some or all of the above respects.